We do not allow images to be attached to the forums as it fills up the database with images. It's preferable to just keep images off the board. If seen forums that had tons of images and years later all those threads with images have "image not longer available" or something similar when the images are moved. It makes the forums look tacky when that happens, so I would prefer no images please. If I post an image it is one that I've uploaded to the RF media section so it isn't going anywhere years from now.
Now, if you are talking about using the "Pinterest" button at the bottom of threads for some reason, you have to be logged in at Pinterest to do that but I don't think we have many images on here.